In a next-generation cellular system, it has been examined to use DFT-S-OFDMA (it is an abbreviation for Discrete Fourier Transform Spread Orthogonal Frequency Division Multiple Access, and is also referred to as SC-FDMA (Single Carrier Frequency Division Multiple Access) or DFT Precoded OFDM) as an uplink communication method. A DFT-S-OFDMA signal has features to arrange a signal in continuous subcarriers, and to have a property of a signal of a single carrier method. Consequently, it can be said that DFT-S-OFDM is a method with an excellent PAPR (Peak to Average Power Ratio) characteristic. Further, a communication method called Clustered DFT-S-OFDM has been proposed for the purpose of improving a spectrum efficiency. This method is the method in which a frequency signal generated by DFT-S-OFDM is divided into groups configured with a plurality of subcarriers called Clusters to thereby non-contiguously utilize a frequency, deterioration of the PAPR characteristic is allowed, and in which a frequency selection diversity effect and the spectrum efficiency are enhanced.
In addition, a transmit diversity technique is under review in which same data are transmitted from a plurality of antennas to thereby improve a reception characteristic. Although there are various transmit diversity techniques, they can be roughly classified into two: one is open loop transmit diversity which does not need channel state information at a transmission side (hereinafter referred to as OLTxD), and the other is closed loop transmit diversity which needs the channel state information at the transmission side (hereinafter referred to as CLTxD). One of the CLTxD is a method for controlling a phase of each transmission antenna to improve reception sensitivity (hereinafter, referred to as precoding), and various discussions have been made thereon.
Precoding includes a case where precoding common to all frequency bands to be used is performed and a case where different precoding is performed depending on the frequency band. Hereinafter, in the present invention, a transmission method which performs same precoding in all frequency regions to be used is referred to as single precoding, and a transmission method which performs different precoding for each frequency region is referred to as multiple precoding. Non-Patent Document 1 has described an advantage of performing different precoding for each frequency region.